Download Overview of Popular Diets - Obesity Action Coalition

An Overview of
Popular Diets
By Jacqueline Jacques, ND
Americans seemingly have a love affair with dieting.
In the year 2000, American consumers spent $34.7
billion out-of-pocket dollars on weight-loss products
and programs – a number that experts suspect
continues to climb1. On any given day if you check
out the New York Times best-seller list, you will
likely find at least two diet books in the top 10 list
for non-fiction. When I looked this week, it was
The Volumetrics Eating Plan by Barbara Rolls, PhD
and The Extreme Fat Smash Diet by Ian K. Smith.
Wait a month, and these will likely be replaced by
something new.
Since roughly two-thirds of the American public
is either overweight or obese, the real question is:
Do any of these plans result in the desired goal
of getting weight off and keeping it off? After all,
the advice always given to those who need to lose
weight is to diet and exercise. When this fails to
produce the desired result, the blame is always put
Diet (v. intr.): To eat and
drink according to
a regulated system,
especially so as to lose
weight.
– American Heritage Dictionary
back on the dieter. Naturally then, the golden ticket
everyone is looking for is the perfect program that will
help people both lose weight and maintain weight-loss.
So, those seeking the answer invest year after year in new
diet books and programs and new hope.
Benefits to Diets
What will follow here is a brief overview and review of
a handful of popular diet systems. Since it is currently
impossible and unreasonable to state that any of them will
produce a long-term result for weight-loss, I tried to place
the emphasis on other factors, such as how healthy and
scientifically sound the program is.
While short-term weight-loss can be achieved by many
means, healthier programs that teach good dietary habits
seem more likely to have other positive health outcomes.
Moreover, there are some weight-loss trends that are
potentially unhealthy in terms of the foods and eating habits
they promote.
Another important way to evaluate the potential benefit of a
diet is to look at what has worked for the people who have
effectively lost weight and kept it off. The National Weight
Control Registry is an ongoing investigation that started in
1994.
The registry enrolls adults over the age of 18 who have
lost 30 or more pounds and maintained their weight-loss
for more than 12 months. They are currently monitoring
the behaviors and characteristics of approximately 5,000
successful individuals, and have published more than a
dozen papers on their findings. Some of the keys to success
found to be common among their subjects are listed in the
box to the right.
Popular Diet Systems
Sometimes it is true that there is nothing new under the sun.
Though there are hundreds of diets all claiming to have the
single best method for you to lose weight, there are really
very few differences between them. It is, therefore, easiest to
look at diets by classifying them into their basic strategies.
Despite the many names they go by and the small
variations, most diets can fit easily into a few discrete
categories Therefore, rather than look at dozens of programs
individually, this article will focus on the categories and give
examples for each. This list breaks down the diets as follows:
Dieting Keys to Success
Eat breakfast. Approximately 78 percent of
those successfully maintaining an average weight-loss
of approximately 70.5 pounds for six years eat breakfast
every single day4.
Restrict serving sizes. There is no
successful weight-loss or maintenance that does not
restrict overall intake of food5.
Limit fat intake. Successful dieters also tend
to limit calories from fat to between 23 and 25 percent
of their total calories6.
Select healthy foods. Along with selecting
low fat foods, successful dieters tend to eat more foods
that are high in fiber, more fruits and vegetables and
fewer high calorie drinks (especially soda).
Use a scale. While some diet programs promote
other means such as measurements or the fit of your
clothes, 75 percent of those with long-term success
report weighing themselves at least once per week7.
Exercise regularly. Not all diet programs
have their own exercise regimen, although many
recommended physical activity. Exercise has been
shown to be important to weight-loss maintenance, with
one-hour per day of moderate intensity exercise being
a common habit among those keeping their weight off
long-term8.
Limit food variety. A common diet strategy
is the limitation of food choices – the extreme being
meal replacement programs where dieters are only
given the choice of shakes or bars for many months.
Studies of successful dieters show that they tend to
limit their food variety from all food groups9.
1. Low Calorie. While virtually all the programs
mentioned here restrict calories to some degree,
there are programs that use calorie control or
reduction as the primary method or philosophy of
weight-loss.
2. Low Fat. Fat is the most caloric of the
macronutrients and diets high in fat may
contribute to some chronic diseases. For these
reasons, low-fat diets have been a mainstay of the
weight-loss world for many decades.
3. Insulin Controlling. Insulin
is a hormone that helps regulate both blood
sugar and the way that the body stores calories
as fat. Especially with the surge in diabetes, diets
that focus on the control of insulin and blood
sugar using a variety of methods have become
increasingly popular.
There are also strategies that fall into some other classifiable
categories:
1. Food Combining
2. Mono-Diets
3. Cultural Diets
Finally, there are few diets that are so unique that they don’t
readily fall into any of these categories, and for the purpose
of our discussion will simply be classified as “other.”
Low Calorie Diets
The gold standard of dieting is the low calorie diet.
Fundamentally, for any weight-loss program to work, the
calories taken in have to be less than calories taken out.
There are actually two classes of low calorie diets.
The Low Calorie Diet (LCD) restricts food intake to
between 800 and 1500 calories per day and the Very Low
Calorie Diet (VLCD) generally restrict dieters to between
500 and 800 calories per day. VLCDs should only be
done under strict physician supervision because of the
medical risk associated with them. LCDs are often done
under physician supervision, but many programs are
also available direct to consumers.
LCDs and VLCDs tend to produce very good short-term
weight-loss, with 12-week averages of 13 to 40 pounds
lost. While more weight is initially lost with a VLCD,
the weight-loss tends to equalize at around six months
due to decreased compliance with the VLCD over time.
For this reason, the safer LCDs are more commonly
used.
The biggest challenge with either type of program is
keeping weight off. Most of these programs utilize
some form of meal replacements such as shakes, bars,
soups or pre-packaged foods to help dieters in making
food choices, and in accurate calorie control. However,
when people stop using the fixed meal replacements;
however, many migrate back to pre-diet foods at prediet portions. Studies looking at five year results on
either form of program show that most people regain all
weight initially lost10. Dieters who adhere to behavior
modification and exercise have been shown to be more
successful at keeping weight off long term11.
Research
in
Diets
When we look at research on long-term outcomes
of diet as a treatment for obesity, the results are not
encouraging. In a recent review using Medicare treatment
criteria, researchers from the University of California
Los Angeles reviewed controlled trials of a variety of
dietary interventions for weight-loss. They concluded the
following:
“… the benefits of dieting are minimal. Sustained
weight-loss was only found in a small minority
of participants, whereas complete weight regain
was found in the majority. Beneficial health
outcomes have not been consistently or frequently
demonstrated in the long term, and very few studies
were able to show clinically significant health
benefits that persisted after weight regain2.”
The UCLA researchers found more evidence that dieting
behavior is predictive of weight gain than it is of weightloss. They concluded this because by and large, studies
that tracked long-term maintenance of weight after a
diet found that not only did people regain weight, they
regained more than they lost initially.
This is not entirely new news in the medical community.
The American Dietetic Association 2002 position paper on
Weight Management also projected minimal benefit for diet
and exercise plans. They state:
“Currently, available data on lifestyle weight-loss
interventions indicate that they produce low levels
of sustained loss. Typically reported weight-losses
remaining after four to five years are about three to
six percent of initial body weight3.”
This means that from the data they reviewed, a 250pound dieter could expect to maintain a weight-loss of
seven to 15 pounds after four to five years.
It is important to note that there are health benefits from
even small amounts of sustained weight-loss, especially
for control of blood sugar and blood pressure. Still, if we
consider the resolution of overweight or obesity to be a
primary goal of dieting, the results are simply not there
for most people.
Examples of Low Calorie Diets and Very Low Calorie Diets include:
Optifast® (Novartis Medical Nutrition), Medifast® (Jason Pharmaceuticals, Inc), Slimfast
(Unilever), HMR (Health Management Resources) and the Cambridge Diet.
Low Fat Diets
Low fat diets were very popular in the 1980’s and 1990’s
and many low fat programs have maintained a large base
of adherents. The principle of low fat diets is simple:
fat has more calories per gram (nine) compared to
carbohydrate and protein (which each have four). Reduce
the fat in your diet, and you reduce the calories and you
lose weight.
Most low fat diets reduce intake from fat to between 20
and 30 percent of total calories. There are some very low
fat diets (Pritikin being an example) that reduce fat intake
to below 20 of total calories. As the general public grows
weary of the high-protein regimens that have held sway
for the past 10 years, some of these low-fat principles
are re-emerging with more modern twists. Volumetrics,
with its emphasis on bulky/filling low fat foods (bigger
volumes to fill you up, with low fat to keep calories in
check) is an excellent example.
As with many diets, short-term weight-loss has been
demonstrated with low fat programs. Reviews of
randomized controlled trials have shown that overall
results vary little from other types of plans, and that
maintained weight-loss after 12-18 months only averages
4.4 to 8.8 pounds12.
Low fat diets have often been pointed out as healthier
than other types of diets, and it has been proposed that
they may reduce other health risks such as heart disease
and cancer. While some small trials do demonstrate these
benefits, larger trials have not shown the benefits to be
significant.
losing weight does not impart any reduction in cancer or
heart disease risk.
Currently the best selling diet book in the U.S., and
having been given thumbs up by Consumer Reports17,
Volumetrics (Barbara J. Rolls, PhD), is rapidly recharging
the interest in low fat dieting. The general difference
between Volumetrics and other low fat diets is the
emphasis on eating large portions of foods that provide
minimal calories (soups, salads, fruits and vegetables) so
that you feel full due to the volume of food eaten.
A recent study compared a standard low calorie diet to
the Volumetrics diet. At one year, researchers found that
those following the Volumetrics principles lost 3.5 pounds
more (17.5 pounds versus 14 pounds) while eating about
25 percent more food18. The Weight Watchers program,
which has been around for about 45 years, is not only
still popular, but has been studied in controlled trials.
Weight Watchers is famous for their patented formula
that assigns points to servings of foods with the goal of
simplifying calorie counting. Studies of Weight Watchers
show that long-term (two year) adherents tend to maintain
a 5 percent weight-loss, and have improvements in blood
pressure, cholesterol, blood sugar and insulin levels19.
Insulin Control
Following two decades of low-fat dieting, Americans were
swept up by a new wave of weight-loss plans that were
focused around controlling the hormone that signals the
body to store fat – insulin. There are really two versions
of insulin controlling diets: Low Carbohydrate (also called
High Protein) and Low Glycemic.
The Women’s Health Initiative Dietary Modification
The general principles are the same – some foods
Trial followed approximately 19,000 women on a low fat
(especially simple sugars and starches) cause a greater
diet for 13 years. They found no reduced risk of breast
surge of blood sugar and a bigger release of the hormone
cancer13, colon cancer14, or cardiovascular disease15. They
insulin. The low carbohydrate programs
also did not see any difference in
take the strategy of dramatically reducing
weight from women who did not
overall carbohydrate content of the diet
Examples of Low
modify their diet to lower fat16.
in place of a much greater percentage
The primary reason proposed for
Fat Diets include:
of protein (and, in some cases, fat). The
the lack of health risk reduction
Volumetrics, the Ornish
Low Glycemic (Low GI) diets allow
was the lack of weight-loss.
Plan, the Pritikin Diet,
adherents to eat a much greater range of
Excess body weight is a known
Weight
Watchers,
food so long as the carbohydrates they eat
risk factor for all of these
vegetarian diets and Fit
have a minimal impact on raising blood
conditions. Thus, it appears that
sugar levels. Some of these programs also
for Life.
following a low fat diet without
Examples of diets that use insulin control
include: the South Beach Diet, the Atkins Diet, The
encourage more frequent eating of smaller meals, the
theory being that this helps to keep blood sugar from
rising and falling throughout the day.
Most studies have not shown insulin controlling diets
to be any better than other forms of dieting for overall
weight-loss. A 2004 study that compared low-carb to
low-fat dieting found that after 11 months, the weightloss in the two groups was virtually identical20.
A much more recent study, however, came up with
different and interesting results. In this trial, researchers
randomly assigned dieters to either a low-glycemic or
low fat diet21. They followed participants for 18 months,
tracking not only weight but also insulin secretion,
cholesterol and triglycerides. After 18 months, it was
found that those with the highest baseline insulin
secretion that followed the low-glycemic diet lost the
most weight and had the greatest health improvements.
What this may tell us is that some diets work better for
people with specific health conditions – in this case,
that people who have high insulin secretion have better
success on a diet that helps to control their insulin
secretion.
These programs vary a lot in the way they allow dieters
to select foods, when and how they suggest eating and
in supportive areas like exercise. Several of them are
“phased,” meaning that dieters start with a very low
carbohydrate introductory period and work their way up
to a more varied eating plan.
In these programs (such as Atkins and South Beach), the
goal is to have the body in a state of ketosis (where the
body is actively burning and using fat for energy instead
of carbohydrate). Because of this, individuals with
kidney disease should not engage in low-carbohydrate
dieting without physician supervision.
Cultural
Cultural diets are often based on the thinking that
because people from a certain place who eat a certain
way are healthier than you are, eating like they do
will allow you to obtain a similar health status. The
Mediterranean Diet is probably the best example of a
cultural diet that has attracted a lot of attention from
the medical community. This diet is high in fish, whole
grains, beans, vegetables, olive oil (monounsaturated
fat), red wine and fiber.
Zone, Protein Power, Sugar Busters, Nutrisystem, The 3Hour Diet and the Extreme Fat Smash Diet.
While not specifically studied for weight-loss, the
large scale Lyon Diet Heart Study, did suggest that
the Mediterranean diet is very beneficial for the
cardiovascular system. After 46 months, subjects
following the Mediterranean-style diet had a 50 to 70
percent lower risk of recurrent heart disease22. Other
examples of cultural diets include the Okinawa Diet
and the Sonoma Diet.
Food Combining
Adherents to food combining diets believe that the
body processes particular combinations of foods
differently from other combinations. Some examples
of this thinking include the idea that starches should be
eaten separately from proteins and fats, fruits should
be eaten on an empty stomach, or that foods should be
eaten at specific times of the day.
While some of these programs are healthy in the foods
that they recommend and are low calorie (which can
result in weight-loss), there is no scientific evidence
that specific combinations of foods will produce more
weight-loss, burn fat more efficiently or impart other
health benefits. Some examples of food combining diets
include Fit for Life, the Schwarzbein Principle, the
Beverly Hills Diet and the Suzanne Somers diet.
Mono Diets and Miracle Foods
Every once in a while you may be standing in the
checkout line at the grocery store and catch a magazine
cover praising some miracle food for weight-loss.
These diets are usually based on eating large amounts
of a single food for a period of time, or adding
a “miracle” food to a strictly
controlled diet to
enhance metabolism
or weight-loss.
Virtually all
mono diets and
miracle food
diets will produce
acute weight-loss,
but they are not
healthy, balanced or
sustainable as a real
References:
weight-loss method. Examples of these concepts include
the Grapefruit Diet, the Cabbage Soup Diet, the Apple
Cider Vinegar Diet and the Milk Diet.
Other
The Fat Flush diet was developed by Anne Louise
Gittleman23. The program claims to promote weightloss by cleansing and detoxifying the liver and thereby
promoting better metabolism. The program is phased
and eventually it ends up looking like a standard lowcarbohydrate diet. While the idea is interesting, there is no
current scientific evidence to support the concept of “fat
flushing.”
The Blood Type Diet was developed by Dr. Peter
D’Adamo who published the book Eat Right for Your
Type in 199624. The theory put forth by Dr. D’Adamo
is that blood type is a genetic fingerprint more powerful
than race, culture or geography.
He believes that sickness is caused by negative reactions
between complex molecules in foods (lectins) and
markers on the cells of the body. The book purports that
eating foods that “agree” with your blood type will reduce
your risks for cancer, heart disease, diabetes, infections
and cancer. The author and other adherents believe that
eating the foods deemed appropriate for your blood type
will assist with weight-loss.
Conversely, eating the wrong foods can cause all sorts
of health problems. If carefully examined, the bloodtype diet is really a low calorie diet with intakes of 1,150
to 1,250 calories per day. Beyond that, the diet may be
difficult to follow due to many restrictions and hard-tofind foods, and no evidence exists to prove that it would
be more beneficial than any other low-calorie program.
About the Author:
Jacqueline Jacques, ND, is a Naturopathic Doctor
with more than a decade of expertise
in medical nutrition. She is the Chief
Science Officer for Catalina Lifesciences
LLC, a company dedicated to providing
the best of nutritional care to weight-loss
surgery patients. Her greatest love is
empowering patients to better their own
health. Dr. Jacques is a member of the
OAC National Board of Directors.
1. Bryant, J., Fat is a $34 Billion Business, Atlanta Business Chronicle
(Sept. 24, 2001), citing research by Marketdata Enterprises, Inc.
2. Mann, T, et al. American Psychologist, April 2007; vol 62: pp 220-233.
3. Weight Management. J Am Diet Assoc. 2002;102:1145-1155
4. Wyatt HR, Grunwald OK, Mosca CL, Klem ML, Wing RR, Hill JO
(2002). Long-term weight-loss and breakfast in subjects in the National
Weight Control Registry. Obesity Research; 10:78-82.
5. Shick, S.M., Wing, R.R., Klem, M.L., McGuire, M.T., Hill, J.O., &
Seagle, H. Persons successful at long-term weight-loss and maintenance
continue to consume a low calorie, low fat diet. Journal of the American
Dietetic Association, 1998, 98, 408-413.
6. Ibid.
7. Klem, M.L., Wing, R.R., McGuire, M.T., Seagle, H.M., & Hill, J.O. A
descriptive study of individuals successful at long-term maintenance of
substantial weight-loss. American Journal of Clinical Nutrition, 1997,
66, 239-246.
8. McGuire, M.T., Wing, R.R., Klem, M.L., Seagle, H.M., & Hill, J.O. Longterm maintenance of weight-loss: Do people who lose weight through
various weight-loss methods use different behaviors to maintain their
weight? International Journal of Obesity, 1998, 22, 572-577.
9. Raynor, H., Wing, R.R., Phelan, S. (2005) Amount of food group variety
consumed in the diet and long-term weight-loss maintenance. Obesity
Research, May;13(5):883-890.
10. Methods for voluntary weight-loss and control. NIH Technol Assess
Statement Online 1992 Mar 30-Apr 1 [2007 Jun 10]; (10).
11. Wing RR,Jeffery RW,Burton LR,Thorson C,Nissinoff K,Baxter JE:Food
provisions vs. structured meal plans in the behavioral treatment of
obesity. J Consult Clin Psychol20:56–62, 1996.
12. S. Pirozzo, C. Summerbell, C. Cameron, P. Glasziou (2003) Should we
recommend low-fat diets for obesity? Obesity Reviews 4 (2), 83–90.
13. Prentice RL, Caan B, Chlebowski RT, et al. Low-fat dietary pattern and
risk of invasive breast cancer: the Women’s Health Initiative Randomized
Controlled Dietary Modification Trial. JAMA 2006; 295:629-42.
14. Beresford SA, Johnson KC, Ritenbaugh C, et al. Low-fat dietary pattern
and risk of colorectal cancer: the Women’s Health Initiative Randomized
Controlled Dietary Modification Trial. JAMA 2006; 295:643-54.
15. Howard BV, Van Horn L, Hsia J, et al. Low-fat dietary pattern and risk
of cardiovascular disease: the Women’s Health Initiative Randomized
Controlled Dietary Modification Trial. JAMA 2006; 295:655-66.
16. Howard BV, Manson JE, Stefanick ML, et al. Low-fat dietary pattern
and weight change over 7 years: the Women’s Health Initiative Dietary
Modification Trial. JAMA 2006; 295:39-49.
17. Consumer Reports, June 2007; pp 12-17. Nancy Metcalf, senior project
editor, Consumer Reports
18. Ello-Martin JA, Roe LS, Ledikwe JH, Beach AM, Rolls BJ. Dietary
energy density in the treatment of obesity: a year-long trial comparing 2
weight-loss diets. Am J Clin Nutr 2007 85: 1465-1477.
19. Heshka S, Anderson JW, Atkinson RL, Greenway FL, Hill JO, Phinney
SD, et al. Weight-loss with self-help compared with a structured
commercial program: a randomized trial. JAMA. 2003;289:1792-8.44.
20. Stern L, Iqbal N, Seshadri P, et al.: The effects of low-carbohydrate
versus conventional weight-loss diets in severely obese adults: One year
follow-up of a randomized trial. Ann Intern Med 140:778-785, 2004.
21. Ebbeling CB, Leidig MM, Feldman HA, Lovesky MM, Ludwig DS.
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22. Kris-Etherton P, Eckel RH, Howard BV, St Jeor S, Bazzarre TL. AHA
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Association Step I Dietary Pattern on Cardiovascular Disease;
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23. Gittleman, Ann Louise and Sears, Barry. The Fat Flush Plan. Mc-Graw
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Solution to Staying Healthy, Living Longer & Acheiving Your Ideal
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